Vat dye compositions and application thereof



Patented! Dec'. 17,1935

I UNITED} STAT VAT DYE CODIPOSITIONS APPLICATION THEREOF Herbert A. Lubs and John Elton Cole, Wilmington, Del., assig'nors to E. I. du Pont de Nemours & Compa y, Wilmington, DeL, a corporation of Delaware No Drawing. Continuation of application Serial No. 504,274, December 23, 1930. ,tion December 19, 1933, Serial No. 703,156

23 Claims.

This invention relates to the art of applying vat dyes to textiles, and more particularly to the art of textile printing. It also relates to new vat dye compositions.

This application is a continuation ofour copending application, Serial No, 504,274 filed December 23, 1930. It also contains subject matter disclosed in our co-pending application Serial No. 703,155.1i1ed December 19, 1933.-

Except for indigo, vat dyes (which are unlike all other types" of dyes both in properties and mode of application to the fiber) were not known prior to the beginning of the present century.

By the term vat dye is meant a colouring maton reduction into a so-called leuco compound, which is soluble in alkalis, and in such a solution, termed a vat, the actual dyeing process is effected; on removing the material from the bath and exposing to the air oxidation takes place, the dye being precipitated on the fibre in insoluble form;

From page 423 of A Textbook of Dye Chemistry by Georgievics and Grandmougin (1920). In the application of vat dyes to textile fibers, a distinction is to be made between dyeing (that is, coloring of the entire fabric) and printing, in which only a portion of the fabric is colored. The mode of applying the dye in each case is different.

The process of dyeing comprises suspending the insoluble vat dye in an alkaline solution and thereafter adding a reducing agent to change ter insoluble in water, but which can be converted the vat dye to its hydro derivative (the reducing agent may also be added before or simultaneously with the dye). The fiber is then steeped in the solution of the. hydro derivative (referred to above as leuco compound) and is removed as soon as a sufiicient amount of the leuco body solution has been absorbed. Exposing the soaked fabric to an oxidizing influence, usually the oxygen of the atmosphere, regenerates the vat dye on the fiber producing a dyed material.

There is an alternative process known as padding which is used to some extent at present. According to this process the fiber is immersed in a suspension of a vat dye until a sumcient quantity of the dye has adhered mechanically to the fiber (this adherence is analogous to wet sand clinging to stick used for stirring a sand and water mixture). Thereafter the fiber, with the dye particles mechanically held thereon, is immersed in an alkaline solution containing a reducing agent whereby the dye par ticles are reduced to the soluble deriva- This applicative, penetrate the fiber and, upon removal from the solution followed by oxidationyare regenerated, resulting in a dyeing taking place as in the general process first described. As will be obvious, some of the dyeis lost from the fiber by reason of going into solution in the vat. If this process is continued long enough, sufllcient dye would be removed from the fiber to render the reducing solution a dye vat of ordinary concentration. Inasmuch as a reduction to the hydro derivative is necessaryboth in dyeing from a solution and by the padding method, the so1ution-dyeing process is the one most widely used where space and equipment permit.

While various reducing agents may be used in the dyeing (as differentiated from printing) of vat dyes, the one most commonly utilized is a hydrosiilfite.

For some years past solid 'hydrosulphiteof soda, containing amounts of Nazsaoi varying 0' from 60 to 95 per cent., has been in the -market in the form of a dry,almost white, powder It is largely used in the dyeing of indigo and other vat dyes, but, owing to the rapidity with which its solutions oxidize in contact with the air, it 5 is not suitable for textile printing.

From page 250 of the Principles and Practice of Textile Printing by Knecht 8: Fothergill (1924) As indicated in the above quotatio the ordinary reducing agent utilized in the dyeing 01.

vat dyes cannot be used practically in the printing of vat dyes on textile. This is a serious disadvantage because vat dye printing is, for other reasons, much more complicated than vat dyeing. I This particular difficulty has been partially overcome by the discovery and commercial production ofthe compound sodium formaldehyde sulfoxylate which only exerts its reducing influence at elevated temperatures. By use of this and equivalent compounds the vat dye can be imprinted on a fabric in the desired design and thereafter reduced and fixed to the fiber.

At the present time, the most extensive textile printing is done with cylinder or roll printing machines. ess are simple and. comprise passing the cloth to be printed under some tension and pressure over an intaglio metal roll, the engraving of which is filled with a printing paste. After leaving the printing machine, the printed cloth is quickly 0 passed into a drier. This dries the printing paste on the cloth in its proper place and prevents the dye from spreading to other portions of the fabric with consequent ruination of the design (in dyeing with vat dyes, spreading of the colorsolution over The fundamental principles in this procy the entire cloth is earnestly sought for, but in the printing of vat dyes, the slightest spreading of the color destroys the value of the printed cloth to such an extent that the same is not salable).

The printing paste applied to the cloth from theroller is a material thickened to such an extent that it does not run readily. It varies with different fabrics and manufacturers, but usually consists of a mixture of unreduced vat dye, a strong reducing agent such as sodium formaldehyde sulfoxylate, an alkali and a thickening agent. The thickening agent is usually a gum (for instance, British gum) starch, or both. The printing paste is usually prepared .by mixing a dye paste or pastes with the other ingredients enumerated, said other ingredients being in the form of a gummy mixture hereinafter called 'printing gum.

The dye pastes are essentially finely divided suspensions of dye with or without a dispersing, agent. These dye pastes (hereinafter referred to as dye pastes, dyestufi pastes or color pastes) usually have the dye suspended in water.

In order to complete the printing, the cloth, after leaving the drier, is passed into an ager (usually a steam ager) for a period of a few minutes, during which time the vat color undergoes reduction (the sodium formaldehyde sulfoxylate in the printing paste producing its reducing action because of the elevated temperature in the ager) and passes to the fiber. The fabric is then subjected to oxidizing conditions which may include passing it into a steeping bath, usually of water or water containing an oxidizing agent. Any excess color is washed off in a soap solution with which the textile material is treated following the steeping.

j Vat dyes at the time of printing are not in true solution. For this reason, the effecting of complete reduction of the dye and the transfer of the color to the fabric in the brief time which the goods are steamed is a process accompanied by great difficulties, as previously stated. In order to make sure that satisfactory resultsare obtained, it is important that the dye paste be of special fineness, but even then a great deal of color is lost because of its failure to dye the cotton. This excess color is washed oif during the soaping which follows the steaming.

In both dyeing and printing it has been proposed to assist the process by the addition of various substances, for convenience called assistants. The purpose forwhich such assistants are added and the functions which they perform may vary widely. Thus, in dyeing, some assistants are added to speed up reduction of the dye, others to retard oxidation of the vat. It does not follow, however, that more brilliant and brighter one, a dioxyanthraquinone or a sulphonic acid 1 of one of these, to the stock-vats and to the dyevats. The action of the anthraquinone-and its derivatives in the vat is due to the ease with which they are reduced and to their power of acting as hydrogen carriers. This latter prop- 6 dyeings are obtained. The same is true of print- 0v in erty enables them themselves to exert a reducing action upon the vat-dyestuif used; this enhancement of the reducing power of the vats is also favourable for the setting and working of the vats, because on the one hand the dyestuff is reduced more quickly and on the other hand the oxidation of the vats is better checked. This patent indicates that substances such as anthraquinone act as assistants in reducing the dye and in checking oxidation, thereby effecting 10 a better utilization of the dye, but it does not indicate that better dyeings are obtained. Similarly, Remlein, U. S. Patent No. 1,750,942, discloses a padding process (defined above) in which anthraquinone is used, although its use is not I claimed nor is its function given.

The following tests indicate that anthraquinone does not in fact give stronger dyeings:

A cotton skein was introduced into a vat whose volume in cubic centimeters was approximately 2 twenty times the weight of the skein in grams. The vat was maintained at a temperature of about F. and contained 5% of a color paste comprising approximately 12% 6:6-diethoxy thioindigo, about 4% caustic soda and about 1: 7.5% sodium hydrosulfite (all percentages based on the weight of the skein). The reduction took place at about F. The skein was then oxidized and soaped in the well known manner.

A similar dyeing, except that the vat contained a one gram of anthraquinone per liter of solution, was judged to be only about 33% as strong as the dyeing made from the vat in which no anthraquinone was present.

On account of the greater complexities, it is 3 much more difficult to obtainv suitable assistants for printing than for dyeing. However, a number of such assistants have been proposed. One such compound is tri-ethanolamine (U. S. Patent No. 1,790,950) and with it markedly improved re- 4 sults have been produced. Another compound which has been proposed for this use is beta:beta'dihydroxy-diethyl ether (British Patent No. 368,910). Further examples might be given without adding anything to the discussion 4;

of the prior art.

Practical experience has shown those skilled in the art the utter futility of attempting to predict what substances will or will not be good assistants in dyeing and/or printing; or that assistants in dyeing produce stronger and brighter printings; or that assistants in printing produce stronger and brighter dyeings. It is well recognized by those skilled in the art, and is therefore worthy of note, that assistants in dyeing and printing other types of dyes cannot be expected to be assistants in dyeing and printing vat dyes because the mechanisms of the reactions involved are different.

It is an object of this invention to produce new (I;

printing gums, improved dye pases and to pro- 7;

vide new and improved results in textile printing. Still further objects will appear hereinafter.

These objects are accomplished by the-productlon of dye compositions comprising an indigoid dye, or mixture of indigoid dyes, containing as an 7 assistant an alkali metal or ammonium salt of anthraquinone-Z-sulfonic acid, or a mixture of said salts, and by the application of such compositions to textile fibers and fabrics. The new printing assistants may be used alone or in conjunction with other assistants. They may be incorporated into the dye paste, printing gum, or printing paste either as such or in the form of the free sulfonic acid. It will be recognized that the free sulfonic acid may be converted to the alkali metal salt by reaction with alkalis such as are present in the printing gum or printing paste. Strong alkalis also tend to replace weak alkalis such as ammonia. 1

The invention will be further understoodfbut is not limited, by the following examples.

Ezrdmple I A thickener was prepared containing 10%- wheat starch, 30% British gum and 60% water. From this thickener a printing gum consisting of r Percent Thickener 57.5 Potassium carbonate 16.0

Sulfoxite C (sodium formaldehyde-sulfoxywas prepared. This printing gum was made into a printing paste by incorporating therein a dye paste of 4:4-dimethy1-6:6'-dichloro-thioindigo.

and anthraquinone-2-sodium sulfonae. The percentage. composition of the printing paste was as follows:

This product was printed on textile material which was then aged and developed in the usual and well known way. .'The prints obtained were from 10 to 25% stronger than those obtainedfrom a similar composition which differed only in the omission of the anthraq'uinone-Z-sodium sulfonate'.

The percentage composition ot the resulting printing paste was as follows:

- Percent Printing gum '79 Dye paste--- 20 Silver sal 1 a i 1 Another paste, similar in all respects except that A'thickener consisting of 10% wheatstarch,

This printing gum was made into a printing paste by stirring the same with a 20%. dye paste of 5:5:7:7-tetra-brom-indigo (C; I. No. 1184, brominationinnitrobenzene) and anthraquinone- 5 2-sodium su1fonate.- After producing a uniform mixture. the printing paste, which was composed of:. 1

Example II v J Percent A printing gum was prepared comprising: Prmtmg gum 59 I I v Percent Dye paste I "1 2o Sil er t 0.5 Thickener 57.5 ta b t was printed on cotton, dried, aged and developed sulfoxit c 11 in the usual way. The prints obtained were more Glycerin? 5 than 10% stronger than those obtainedTrom a Water "Q 10.5

The thickener consisted of: I J

, I Percent Wheat-starch"; 10 Britishgum 30 WBWL. 6O

paste printed under similar conditions which was similar in every respect except that the anthraquinone-Z-sodium sulfonate had been omitted.

Example V 60 1 A thickener was prepared including 10% wheat starch, 30% British gum and 60% water. From this thickener a printing gum consisting of:

Percent Thickener--. -Q 57.5 Potassium carbonate 16 Sodium formaldehyde sulfoxylate 11 Glycerine; 5 Water 10.5

was prepared. This printing gum was made into a printing paste by incorporating therein a dye paste of 5:5z'lzT-tetra-brohr-indigo containing 20% solids (C. 1. No. 1184), anthraquinone2- 30% British gum and 60% water was prepared 10 and made into a printing gum having the following composition:

' Percent Thickener 67.5, Potassium carbonate... 8 15 SulfoxiteC 4 Glycerine 5 Water 15.5

A dye paste-containing 12% of -6:6'-dimethoxy- 20 thioindigo and the sodium salt of .anthraquinone- 2-sulfonic acid were incorporated into the printing gum to produce a printing paste having the following composition:

. p Percent 25 Printing gum 79.5 Dye paste 20 Anthraquinone-2-sodium sulfonate .5

Example IV I 30 A thickener containing 10% wheat starch, 60% water and 30% British gum was prepared and made into a. printing paste having the following percentage composition:

Percent 35 Thickener 67.5 Potassium carbonate 8 Sulfoxite C 4 Glycerine 5 Water 15.5

sodiumwulfonate. The percentage composition of the printing paste was asfollows:

vPercent Printing gum- 79.9 Dye paste (20% dye) 20 Anthraquinone-2-sodium sulfonate 0.1

This product was printed on textile material which was then aged and developed in the usual way. The prints obtained were from 10 to 25% stronger than those obtained from a similar composition which difiered only in the omission of v the anthraquinone-2-sodium sulfonate.

Example v1 A thickener was prepared consisting of 10% wheat starch, 30% British gum and the remainder water. This thickener was incorporated in a printing gum having the following composition:

Percent Thickenen- 56.5 Potassium carb ate 10 Sodium hydroxide 1 Commercial glucose 15 Glycerine 5 Water- 12.5

This printing gum was mixed with a 16% (solids) dye paste of bis-beta-naphthio-naphthene indigo and the sodium salt of anthraquinone-betasulfonic acid to produce a printing paste. Thi

printing paste, being composed of:

, Percent Printing gum 79 Dye paste 20 AnthraquinoneJ-sodium sulfonate 1 was printed oncotton textile material in the well known way.- Comparison of these prints with prints obtained under similar conditions from a similar printing paste which omitted the anthraquinone-2-sodium sulfonate showed them to be about 15% stronger.

Example VII A thickener was prepared consisting of 10% wheat starch, 30% British gum and the remainder water. This thickener was incorporated in a printing gum having the following composition:

Percent Thickener 56.5 Potassium carbonate 10 Sodium hydroxide 1 Commercial glucose 15, Glycerine v 5 Water 12.5

This printing gum was mixed with a 16% solids dye paste of 6:6-difluoro-thioindig6 and sodium salt of anthraquinone-beta-stflfonic acid to produce a printing paste. This printing paste, being composed of V.

Percent Printing gum 79.1 Dye paste 20 Anthraquinone-Z-sodium sulfonate"; 0.9

was. printed on cotton textile material in the well known way. Comparison with prints obtained under similar condition from a similar printing paste which omitted the anthraquinone-Z-sodium sulfonate showed that the (silver salt) paste gave prints about 15% stronger.

Example VIII A thickener was prepared containing 10% Glycerine 5 Water 10.5

wheat starch, 30% British gum and 60% water. From this thickener a printing gum consisting of:

. Percent Thickener I 57.5 Potassium carbonate 16 5 Sodium formaldehyde-sulfoxylate (Rongalite) 11 i was prepared. This printihg gum was made into 10 a printing paste by incorporating therein anthraquinorie-Z-sodium sulfonate and a dye paste of the dye resulting from condensing 5:7-dibromisatin chloride with 3-hydroxy-4-methyl-6- chloro-thionaphthene. The percentage composition of the printing paste was as follows:

Percent Printing gum 79.9 Dye paste (10% dye) 20 20 Anthraquinone-Z-sodium sulfonate 0.1

This product was printed on textile material which was then aged and developed in the usual way. The prints obtained were from 10 to 25% stronger than those obtained from a similar com- 25 position which differed only in the omission of the anthraquinone-Z-sodium sulfonate.

Example IX The printing paste having the following com- 30 position: i

Per cent 5:5 '-dichloro-7 :7 '-dimethyl-thioindigo (20 dye paste) (C. I. No. 1209) 20 "Thickener"- 55 35 i Glycerine 5 Sodium hydrosulfite b 5 Sodium hydroxide (36% strength); 5 Sulfoxite C -5 Water 3 4O Anthraquinone-beta sodium sulfonate 1 was prepared. In the preparation of this composition all of the ingredients except the last three mentioned (namely, the sulfoxite C, water and silver salt, were brought together, uniformly 45 mixed and heated until reduction was complete, whereupon the remaining ingredients were added and the product stirred to uniformity. The thickener in this case consisted of: q

80% of a thickener consisting of 10%; wheat starch 30% British gum 60% water 5% water 15% potassium carbonate 5 This product was printed on textile material which was then aged and developed in the usual way. The prints obtained were stronger than those obtained from a similar composition which differed only in the omission of the anthraquin one-2-sodium sulfonate.

- Water a Anthraquinone 2-sodium sulfonate The method of preparation was as follows:. The

dye paste, thickener, glycerine, NazSaO. and NaOI-I wereuniformly mixed and heated until reduction'was complete. The Rongalite, water and anthraquinone-2-sodium sulfonate were there:

after added. The product was stirred to uniformity. The thickener used was: I

80% of a composition comprising:

10% "wheat starch 30% British gum 60% water I water The product was printed on textile material. This was aged and developed in the usual way. The prints were 10 to,25% stronger than those made with a similar composition from which the anthraquinone-2-sodium sulfon'ate had beerromitted. v

I I Example XI The following ingredients were incorporate into a printing paste:

5:5-difluoro-thioindigo dye paste (10%so1ids) 20 Thickener 55 Glycerine NazSiO: NaQH (36% strength) Sodium formaldehyde -sulfoxylate (Rongalite) 6 The dye, thickener, glycerine, Nazszdi andNaOH were brought together and uniformly mixed. Heat was applied until reduction wasf complete.

Then' the Rongalite, water and anthraquinone-2- sodium sulfonate were added. The product was stirred to uniformity.

as follows:

The thickener used was prepared In a composition consisting of 10% wheat starch,

30% British gum and 60% water, there were stirred K 'and water until" the resultant material was as follows:

. J Per cent Composition 80 Water v KaCOa 15 The printing paste obtained was printed on a textile material and aged and developed as usual. These prints were from to 25% stronger than a corresponding paste without the silver salt.

T Example XII A printing paste of the following composition was prepared:-

The method used in preparation was this: The dye paste, thickener, glycerine, N82S2O4 and NaOH were uniformly mixed and heated to complete reduction. The sulfoxylate, water and anthraquinone sulfonate were added. This product was. stirred to uniformity. The thickener used was made by mixing 10% wheat starch, 30%

British gumand 60%water and to 80% or such Per' cent composition adding 5% water and potassium carbonate. When the product was printed on a textile material, aged and developed, the prints were found to be 10 to 25% stronger than those made without. any anthraquinone-2-sodium 5111- 5' 'fonate. v

Example XIII A thickener was prepared containing 10% .wheat starch, 30% British gum and the remainder water. This thickener was incorporated in a printing gum having the following composition:

Per cent Thickener Y 56.5 Potassium car a 10 15 Sodium hydroxide 1 Preservers syrup Water 7.5 Gly'cerine 5 This printing gumwas mixed with a 12.5% colorpaste of -4: i'-dimethyl-6:6'-dichloro-thioindigo and sodium salt of anthraquinone-beta-sulfonic acid to produce a printing paste. This printing paste, being composed of:

L a Per cent Printing g m J '79 Dye paste 20 Anthraquinone-2-sodium sulfonate '1 was printed on cotton textile material in the well known way. Comparison with prints obtained under similar conditions from a similar'printing paste which omitted the silver salt showed about 20% greater strength in the print from the printing paste of this invention. 9

EzampleXIV A thickener was prepared containing 10% wheat starch, 30% British gum and-the re- 1 mainder water. This thickener was-incorporated in a printin gum having-the following composition: I

Per cent Thickener 56.5

Potassium carbonate 10 5 Sodium hydroxide '1 I Commercial glucose 1 15 Glycerine 5 Water 12.5

This printing gum was mixed with a 20% solids dye paste of 5:5'-dibrom-7:'l'-dimethyl-thioindigo and anthraquinone-beta sulfonic acid ,to produce a printing paste. This printing paste, being composed of:

Printing g I '79 Dye paste 20 Anthraquinone-2-sulfonic acid 1 was printed on cotton textile material in the weil known way. The prints-obtained under similar conditions from a similar printing paste which omitted the anthraquinone-2-sodium sultonate' were about 15% weaker.

Example XV The printing paste having the following composition:

. Per cent 4;4'-dimethyl-thioindigo (10% dye) 20 Thickener 55 Glycerine 5' Sodium hydrosulfite n 5 Sodium hydroxide (36% strength) 5 Commercial glucose 9 Silver sa 1 76 cent 56 J was prepared. In the preparation of this composition all of the ingredients except the commercial glucose, water and silver salt were added, uniformly mixed and heated until reduction was complete, whereupon the remaining ingredients listed were added and the product stirred to uniformity. The thickener in this case consisted of Per cent Water 53 Wheat starch 8 Potassium carbonate British gum 24 This product was printed on textile material which was then aged and developed in the usual way. The prints obtained were from 10 to 25% stronger than those obtained from a similar composition whi'ch'difiered only in the omission of the silver salt.

- Example XVI The printing paste having the following composition:

Per cent Dye paste of the thionindigo dye prepared by well known methods. from 2-thioglycol naphthalene (14% solids) 20 I'hickener 55 Glycerine 5 Sodium hydrosulflte 5 Sodium hydroxide (36% strength) 5 Commercialgluco 9 Anthraquinone-beta-sodium sulfonate 1 was prepared. In the preparation of this composition all of the ingredients except the commercial glucose, water and anthraquinone-betasodium sulfonate were added, uniformly mixed and heated until reduction was complete, whereupon the remaining ingredients were added and the product stirred to uniformity. The thickener in this case consisted of: I

. Per cent Water '53 Wheat star 8 Potassium carbonate 15 British g m 24 This product was printed on textile material which was then aged and developed in the usual way. The prints obtained were from 10 to 25% stronger than those obtained from a similar composition which diflered only in the omission of the anthraquinone-2-sodium. sulfonate.

i Example XVII The printing paste having the following composition:

Per cent Dye paste of the dye resulting from condensing 5:7-dibrom-isatin chloride with 3-hydroxy 4 methyl-fi-chloro-thionaphthene (10% solids) 20 Thickene'r 55 Glycerine 5 Sodium hydrosulfite 5 Sodium hydroxide. (36% strength) 5 Commercial glucose 9 Anthraquinone-2-sodium sulfonate 1 1 was prepared. In the preparation of this-composition all of'the ingredients except the glucose, water and silver salt were added, uniformly mixed and heated until reduction was complete, whereupon the remaining ingredients were added and the product stirred to uniformity. The thickener in this case consisted of:

Per cent Water 53 Wheat starch 8 5 Potassium carbonate 15 British gum 24 This product was printed on textile material which was then aged and developed inthe usual.

was prepared. In the preparation of this composition all of the ingredients except the commercial glucose, water and silver salt were added, uniformly mixed and heated until reduction was complete, whereupon the remaining ingredients were added and the product stirred to uniformity. The thickener in this case consisted of: 35

Per cent Water 1 53 Wheat starch 8 Potassium carbonate 15 40 British gum I 24 This product was printed on textile material which was then aged and developed in the usual way. The prints obtained were from 10 to 25% stronger than those obtained from a similar. com- 45 position which differed only in the omission of the silver salt.

\ Example XIX The, printing paste having the following composition:

. Per cent 4:-i'-dichlor-5:5'-dibrom-indigo.(20% solids dye paste) 20 Thickener 55 Glycerine 5 Sodium hydrosulflte 5 Sodium hydroxide (35% strength) 5 60 Commercial glucoseuii. 9 Anthraquinone-beta-sodiuni sulfonate 1 was prepared. In the preparation of this composition all of the ingredients except the glucose,

water and anthraquinone-beta-sodium sulfonate 66 V were added, uniformly mixed and heated until reduction was complete, whereupon the remaining ingredients were added and. the product stirred to uniformity. The thickener in this case consisted of: l0

Per cent Water 53 Wheat starch 8 Potassium carb 15 British gum This product was printed on textile material which was then aged and developedin the usual way. The prints obtained were from 10 to 25% stronger than those obtained from a similar composition which differed only in the omission of the anthraquinone-beta-sodium' sulfonate.

I e The thickenercontained 10% wheat starch, 30%

British gum and 60% water. A printing paste was .made from the printing gum by adding 6:6- diethoxy-thioindigo (C'. I. No. 1218) dye paste containing 11.5% solids. To this mixture was added milled silver salt (sodium. salt of anthra quinone-Z-suli'onic acid). The resulting print- .ing paste had the following composition:

Milled silver salt 0.1

Two other pastes were prepared, similar in all respects except that in one the silver salt was not milled and in the other the silver salt was omitted. Prints were made from the three pastes under similar conditions. The prints made from the two printing pastes containing the silver salt were 10 to 25% stronger than those made from the paste from which silver salt was omitted. But it is also worthy of notice that those prints made from the paste containing the milled silver salt were noticeablystronger than those printed with the paste containing silver salt which had not been milled.

The thickener contained 10% wheat'starch, 30% British gum and 60% water. This pririting gum was used to make a printing paste by mixing uni- Iormly with a dye paste containing 12.5% of 4:4- dimethyl-6:6'-dichloro-thioindigo and a small amount of milled silver salt. The following proportions were present in the finished composition:

. Per cent Printing gum 79.9 Dye paste. 1

Milled silver salt--. 0.1

Prints made from this printing paste were 10 to stronger than those made from a similar paste in which silver salt was absent, and noticeably stronger than those made from a similar paste which contained silversalt which had not undergone themilling process.

Example XXII A printing gum was made from:

. Per cent Thickener 56.5 5 K2003 Q 10 NaOH 1 Preservers syrup (mainly glucose and tructose) 20 Glycerine p 5 10 E20 7.5

The thickener contained 10% wheat starch, British gum and 60% water. A printing paste was made from this gum by mixing uniformly 1 with a 16% solids dye paste of bis-beta-naphthio-naphthene indigo, and the milled sodium salt of anthraquinone-beta-sulfonic acid in the following proportions:

Per cent 20 Printing gum '79 Dye paste 20 Milled anthraquinone-beta-sodium sulionate- 1 .Prints were made from this paste. These prints were compared with prints made from a similar paste which lacked the presence of the milled assistant. The prints from the paste with the milled silver salt assistant were 10 to 25% stronger than the others. They were also noticeably stronger than prints made from 'a similar paste in which the silver salt assistant used was not milled.

The composition of the thickener herein utilized was 10% wheat starch, 30% British gum and 60% water. This printing .vgum was made into a printing paste with a 5:5'-dichloro-6: 6-dimethyl-thioindigo dye paste containing anthra: 'quinone-Z-sulfonic acid.. The composition of the printing paste was:

, Per cent Printing gum 79 Color paste (12.5% dye solids) 20 Anthraquinone-2-sulfonic acid. 1

This paste gave prints several percent stronger than a similar paste not containing anthraquinone-2-suli'onic acid when printed, dried, aged and developed in the usual way.

Example XXIV I A thickener whose composition was 10% wheat starch, 30% British gum and water, was incorporated into a printing gum whose composition was:

v 1 Per cent Thickener 57.5 Sodium formaldehyde-sulfoxylate 11 Glycerine 5 7o This printing gum was made into a printing paste by mixing the same with appropriate quantities of a 20% dye paste 0! 5:5'- dichloro-7:'l'-dibrom- 7- indigo and a water suspension of anthraquinone- 2-sodium sulfonate which had been milled in water. The composition of the resulting print'-' ing paste was as follows:

Per cent Printing gum 79.9 Color paste 20 Anthraquinone-2-sodium sulfonate 0.1

It is to be understood that the invention is not limited to the specific dyes listed in the above examples. to those skilled in the art and are disclosed in such publications as:

.1. Technologie Der Textilefasern- Kiinstliche Organische Fabstofie H. E. Fierz-David, 1926.

2. Color Index (1924) Supplement 1928), Society of Dyers and Colourists.

3. Fortschritte der TeerfarbenFabrikation 'P.

Friedlaender.

4. Farbstoiftabellen Gustav Schultz (1931).

5. Enzyklopadie der Kiipenfabstoffe Truttwin (1920).

Specific mention may be made of such other compounds as 2:3:2 :3-di-anthraquinone indigo,

indigo, in-

bromo-2-beta-naphthindol-2-indol digo, thioindigo 2- (5:7-dibrom-indol) -2'-anthracene indigo, 2- (5 7 -dibrom-ind'ol) -2'-naphthalene indigo 4:4'-diet hyl-thioindigo, 5:5'-dimethyl-bis-thionaphthene indigo,-bis-alphanaphthindol indigo, 4:516:7z4':5:6':7-octo-chloroindigo, dimethyl-indirubin, dibrom-indirubin, dyes prepared by the condensation of reactive 2-isatin derivatives with naphthocarbazole bodies-(e. g.,

ortho-tolu-5 -hydroxy-alpha-naphthocarbazole) indolacenaphthene indigos, thionaphthene-indolindigos, and the like. The specific dyes of U. S.

Patents Nos. 1,558,252 and 1,792,648 also merit.

particular mention.

Theamount of the assistant is ordinarily varied directly with the amount of solid dye and the paste used, based on a 12.5% solids dyepaste. In printing, the preferred amounts are about 1 to about 5%. Greater or smaller amounts than this may be used when desired. For example, the use of 0.5 to 10% of the assistant'in printing gives good results. Less than 0.5% maybe used if desired, although the result isnot as'noticeable as i that produced by using an amount falling within the preferred range. Generally, more than 10% may be used without detriment to'the printing process.

It will be recognized that the type of reducing agent is to be chosen according to the method to be used in applying the dye to the fiber. Sodium formaldehyde-sulfoxylate is a material well adapted for printing vat dyes, inasmuch as it is not oxidized at ordinary temperatures and exercises its reducing action at elevated temperatures.

This invention is of great technical and cornmercial importance since it has been-found that the presence of assistants of the type described in indigoid printing pastes, and especially in the printing of thioindigoid dyes, makes possible the production of prints of superior strength and brightness to those obtained from a similar printing paste from which the assistant has been omitted. The prints are also much stronger and brighter than printing pastes in which the assistant is a substance such as anthraquinone.

As many apparently widely difierent embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that we do not limit ourselves to Other indigoid dyes are well known ionic acid. 15.

- 3. A dye paste comprising a thioindigoid printing and a substance selected from the group consisting oi'anthraquinpne-Z-sulfonic acid, the ammonium salt of anthraquinone 2-sulfonic acidand alkali metal salts of anthraquinone-2-sul- L fonic acid.

4. A dye paste comprising a thioindigoid prlnting and the sodium salt of anthraquin'one-Z-sulionic acid. 1

5. A printing paste comprising an indigoid dye and an alkali metal salt of anthraquinone-2-sulfonic acid. J

6. A printing paste comprising a thioindigold dye and an alkali metal salt of anthraquinone-2- sulfonic acid. 30

'7. A printing paste comprising 4:4'-dimethyl- 6:6'-dichloro-thioindigo and an alkali metal salt of anthraquinone-Z-sulfonic acid.-

8. A printing paste comprising fizfii-diethoxythioindigo and an alkali metal salt of anthraquinone-2-sulf0nic acid.

9. An indigoid printing'gum comprising an alkali metal salt of anthraquinone-2-sulfonic acid.

10. A thionindigoid printing gum comprising an alkali metal salt of anthraquinone-2-sulionic 40 acid.

11. The process of printing indigoid dyes which comprises applying to the fiber a printing paste comprising the indigoid dye, an alkali metal salt of anthraqulnone-Z-sulfonic acid, printing gum, 5

alkali and a reducing agent suitable for printing, and thereafter drying, aging and developing the print. v

12. In the process of printing indigoid dyes on textiles, the step'which comprises incorporating 50 a substance from the group consisting of anthraquinone-Z-sulfonic acid and an alkali metal salt thereof into the printing paste.

13. In the process of printing thionindigoid dyes on textiles, the step which comprises'incor- 5'. porating a substance from the group consisting of anthraquinone-2-sulfonic acid and an alkali metal salt thereof into the printing paste.

.14. In the printing of textilematerial, the step of printing on the textile material with a printing paste comprising an indigoid dye and an alkali metal salt of anthraquinone-Z-sulfonic acid.

15. In the printing of textile material, the step of printing on the textile material with a printing paste comprising an indigoid dye and-milled sodium anthraquinone-2-sulfonate.

16. The. process of printing thioindigoid dyes which comprises applying to the fiber a printing paste comprising the thioindigoid dye, an alkali metal salt of anthraquinone-2-sulfonlc acid,

printing gum, alkali and a reducing agent suit? able for printing, and thereafter drying, aging and developing the print.

17. The process of printing thioindigoid dyes which comprises applying to the fiber a printing 7 paste comprising a thioindigoid dye, an alkali metal salt of anthraquinone-Z-sultnnic acid, printing gum, potash and sodium formaldehydesulfoxylate, and thereafter drying, aging and developing the print.

i 18. The method of printing with vat dyes of the indigoid type which comprises applying to the goods a composition containing the indigoid dye,

sisting of anthraquinone-2-sulfonic acid and alkali metal salts thereof.

21. The process of preparing printed textile materials which comprises printing on a textile material with a printing paste containing a water- 5 insoluble thioindigoid color, a. printing gum and from about 0.1 to about 1.0% of an alkali metal salt of anthraquinone-2-sul1onic acid.

22. The process of preparing printed materials which comprises printing on a textile material low with '4:4'-dimethyl-6:'6'-dichloro thioindigo in the presence of an alkali metal salt of anthraquinone-Z-sultonic acid.

23. The process of preparingprinted materials which comprises printing on a textile material 15 with 6:6'-diethoxy thioindigo in the presence of an alkali metal salt of anthraquinone-2-sulfonic acid.

HERBERT A. LUBS.

JOHN ELTON COLE. 20

Certificate of Correction Patent No. 2,024,975 December 17, 1935 HERBERT A. LUBS ET AL. It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Page 4, second column, line 39, for Sulfoxite C 5 read Sulfowite C' 6; page 5, first column, line 2, for M 5 0 read Na S O page 8, second column, lines 4, 10, 16, and 22, claims 1, 2, 3, and 4, respectively, for dye read printing; and lines 4, 1011, 1617, and 2223, claims 1, 2, 3, and 4, respectively, for printing read dye; same page and column, line 39, claim 10, for thionindigoid read thioindigoid; and that the said Letters Patent should be read With these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 11th day of February, A. D. 1936.

[sEAL] LESLIE FRAZER,

Acting Commissioner of Patents. 

